Such arrangements include as an essential component a control apparatus having its functions either hardwired or freely programmable using, for example, a microcomputer. Control apparatus of this type have been already described in detail in pertinent technical literature and belong to the state-of-the-art for a long time. These control apparatus are well proven in practice with respect to road behavior and exhaust emission of the internal combustion engine.
On the other hand, the relatively complicated configuration of these control apparatus can lead to possible failure of individual components. A malfunction in a secondary component may tie up the function of the entire control apparatus and thus also the internal combustion engine. To circumvent this disadvantage, many suggestions have already been made as, for example, in patent application WO No. 80/00597. In this patent application, it is suggested that the control apparatus be provided with at least one sensor-controlled auxiliary device the output signals of which, alternatively to the output signals of the control apparatus, are adapted to be applied via a switch-over device to final control stages, for example, to the final control stages of an electric injection system. In this arrangement, the auxiliary devices are controlled by the output signals of the same sensor which is also connected to the control apparatus.